Production and maintenance integrated planning

This paper introduces an expert system for the planning and management of a multi-product and one-stage production system made up of flexible machines operating in parallel. The following characteristics of the production system were considered: production costs depending on the machine and on the job processed, setups depending on the machine and on the job-processing sequence, preventive maintenance, order portfolio defined by order quantities, release dates and due dates. The system schedules both production and maintenance at the same time. It pursues three objectives: to meet release and due dates, to minimize the total cost of the plan (sum of the expected maintenance cost, the setup cost and the production cost) and to minimize the total plant utilization time (sum of the total job processing time, the total setup time, the total machine idle time and the total maintenance time).